Engine-starting motor.



SAMUEL W.' RUSHMORE, OF PLAINFIELD, NEW JERSEY.

ENGINE-STARTING Moron.

Specication of Letters Patent. i Patented July 31, 1917,

Application filed September 27, 1912. Serial No. 722,629.

To all whom t may concern.'

Be it known that I, SAMUEL WILLIS RUSH- MORE, a citizen of the UnitedStates, residing at Plaineld, in the county of Union and `State of NewJersey, have invented new and useful Improvements in Engine-StartingMotors, of which the following isa specification.

This invention is an improved engine star ter for internal combustionengines and is of that type in which an axially movable gear .is broughtinto mesh with an engine fly-wheel to transmit power to the latter and'tc the engine for starting the engine, and is automatically movedaxially out of mesh when the engine takes up its cycle of operation.

The invention resides primarily in themeans for automatically effectingthis engagement and disengagement and the main objects of my inventionare to render such engagement and disengagement more reliable, positiveand instantaneous and without the use of gear-shift levers, ratchetclutches, etc., which, with the necessary interlocking connections,involves considerable complication and expense. My novel arrangementresults in a considerable saving in weight, space required andelectrical energy.

As one important feature of the invention, the shiftable pinion ispulled endwise into mesh by electro-magnetic action resulting from theclosing of the circuitpf the electric motor employed torotategsaiid'pinion.

By Imeans of this arrangement, the faster driving of thearmature'when`the engine takes up its cycle of operation results in anincrease in the counter-electromotive force and a decrease in theendwise magnetic pull which permits a spring or other means to returnthe pinion to its normal disengaged position. As a simple and effectivemeans for accomplishing this, I preferably connect the pinion directlyto the armature shaft and permit the shaft and armature to slide endwisewithin the field of the electricmotor.

As a further important feature, I employ helical gears, the inclinationof the gear teeth being such that the end thrust thereon tends to holdthe axially movable gear in mesh when it is rotated to drive the engineand shifts or aids in shifting it out of mesh when it is rotated by theengine when the latter takes up its cycle of operation.

In the accompanying drawings which show a preferred and desirableembodiment of my invention the parts are designated by similarcharacters in both of the figures which illustrates my inventiondiagrammatically and of which Figure 1 shows the normal disengagedposition of the parts when the motor is inactive and Fig. 2 shows theparts in the position of engagement to start the engine when the motoris ener' gized.

In the figures A indicates an electric motor having series wound fieldoles 2 and 8. 4 is an armature having an e ongated shaft 4 running inbearings 5 and 6. 7 is a helical gear or pinion on the end of thearmature shaft and adapted to engage with the helical gear teeth 8 cutin the rim of the engine fiy wheel 9. 10 is a coiled spring in a bearingbracket 11 attached to the bearing 6 and adapted (as it is compressedbetween the bracket end and the end of the shaft) to force the armatureendwise out of the field a sufficient distance to throw the pinion 7 outof engagement with the fly wheelv gear 8. 12 is an elongated commutatorhaving brushes 14, 15. 16 is a storage battery, 17 a circuit closingswitch and 18 .and 19 are connections arranged to place the battery inseries with the brushes, armature and field windings.

It will be seen that so long as the switch 17 is open the coil spring 10will force the armature 4 endwise out of line with the field poles 2 and3 so that the gears 7 and 8 will be out of engagement as shown in Fig.1.

Upon closing the switch 17, as shown in Fig. 2, a heavy current will atfirst flow from the battery through the armature and field coils, thuspowerfully magnetizing the field poles and causing the latter to exert apowerful horizontal attraction or pull on the armature 4. While in thedisplaced position shown in Fig. 1 the field will not exert its maximumrotative effect upon the armature which will thus at first be movedrapidly in an axial direction, but with less than maximum rotativeeffort owing to the then reduced area of the effective magnetic eld.

The rotation being in the same direction as which the field exerts uponthe armature to draw it into its normal running position in ilo linewith the field magnet poles and it will then exert its maximum torque tostart the engine. Of course the spring will always exert a pressure andthe armature can never reach exact alinement; at very least there willalways be a slightV displacement diiiicult to be shown in the drawing.

After the first few explosions in the engine cylinders the fly wheelwill gain in speed and drive the armature until the speed of the latterbecomes so high that its counter electromotive force will so diminishthe current passing through the motor that there will not be suiiicientmagnetic attraction to hold the armature against the pressure of thespring 10 and the added outward thrust due to the angularity of thehelical gear teeth when the motor is driven by the engine. As will beunderstood the` end thrust due to the angularity of the teeth is thenreversed and the pinion underthe influence of the spring and of theinclined teeth will be moved horizontally out of engagement with the iiywheel gear after which the operator opens the switch 17 and the motorcomes to rest in position shown in Fig. 1. This helical form of teeth isin some cases desirable but is not essential to the.

successful-operation of the invention.

It will thus be seen that I have avoided the use of all gear shiftingmechanism and that by the simple closing of the switch the armature isautomatically thrown into engagement with the gear on the engine wheeland after coming into full engagement the maximum effort will beimparted to the` wheel to cause it to revolve. rihe particulararrangement is desirable for the reason given but it will be understoodthat my device is subject to various modifications without departingfrom the spirit of the invention.

Having described my invention, 1 claim.

1. An engine starting electric motor comprising a field magnet and anarmature axially movable with respect to the eld and normaliy displacedbut adapted to be brought into driving relationwith a device to bestarted thereby, an automatic means for restoring the movable armatureto its normal displaced position, said means being dependent upon theincreased counterelectromotive force developed when the speed isincreased through starting of the device.

2. An apparatus of the class described comprising in combination, anengine starting electric motor comprising a field magnet and an armatureaxially movable with respect to said field and adapted to be broughtinto driving relation with adevice to be started thereby, together withmeans for restoring the armature to its normal displaced position whenthe motor has reached a predetermined speed.

3. In an apparatus of the class described when excited by the normalworking current and to overcome the attraction of the field upon thearmature when the current is reduced by action of the increasedcounterelectromotive force due to increased speed of the motor when-thestarting of the device is effected.

4:. An electric starting motor comprising afield magnet and an armaturearranged to have considerable axial movement within the field, incombination with means for engaging the motor with the device to bestarted through the agency of the axial movement of the armature and tobe actuated by the motor current, and being so arranged that after thedevice has reached a predetermined speed the resultant decrease in thecurrent passing through the motor will cause the automatic disengagementof the motor from the device.

5. An electric starting motor comprising a field magnet and an armaturearranged to have considerable axial movement within the field, incombination with helical gears for engaging the motor with the device tobe started through the agency of the axial movement of the armature andto be actuated by the motor current, and being so arranged that afterthe device has reached al predetermined speed the resultant decrease inthe current passing through the motor will cause the automaticdisengagement of the motor from the device.

6. In starting gearing for automobiles the combination of helical gearadapted to mesh with'each other and transmit motion from a startingmotor to the automobile engine, one of said gears being shiftableaxially out of operative position by the end thrust so 'i caused by thehelical form of the gear teeth 1s frutas@ Y.7aiallrrelatreitthe@engagement therewith Vof the gear teeth beingsuchr-fthtsftm endAisrotated' by the starting motor and will in ,th

ggearinr fo automobiles Ceai'bmaaon zheircaingamaadapted an.

mesh withreach other and transmielimotibn:

fand the inclinato thrust thereon tendsltligolld.theaxially mov ablegear whenlit?Zisirotatedrbyithe starting motor in engagement with theother gear and will shift it out of engagement therewith when it isrotated by the engine, and means vfor shifting said axially movable gearinto engagement with'the other gear at will.

'9. In an apparatus of the class described, in combination, an internalcombustion engine, an electric motor, a'helical gear operativelyconnected to said engine, a second helical gear adapted to mesh withsaid irst gear and normally disposed offset in an axial direction fromits meshing position, and means for moving said second gear endwise intomesh with said first gear, said means comprising an endwise movablemember coaxial with said motor and secured. to said second gear, saidmember being moved endwise solely by solenoid action when said motor isenergized, said gears being automatically disengaged as the motor ceasesto drive the engine when the starting of the engine has been effected.

10. In apparatus of the class described, the combination of an internalcombustion engine, an electric motor, a helical gear operativelyconnected to said engine, a second helical gear adapted to mesh withsaid first gear and normally disposed offset in an axial direction fromits meshing position, and means for moving saidl second gear into meshby solenoid action upon the closing of the motor circuit and thestarting of the motor, the pitch of the gear teeth being such that theaxial thrust thereon hold the shiftable gear in operative position whenit is rotated by the starting motor and will shift it into inoperativeposition when it is rotated by the engine. Y

1l. In an apparatus ofthe class described, the combination of aninternal combustion engine, an electric motor, a source of power,circuit connections whereby said motor may be energized from said sourceof power, a helical gear connected to said engine, a helical gearconnected to said motor and normally oii'set in an axial direction frommeshing position, means adapted to automatically move saidsecond gearaxially into driving engagement with said rst gear byy ifitlintefinoperative;*position when rit yz-gtheengmaraudimeansiforfshiftsovableigear t safidncireu will tend toto mesh?- pull upon the closing ofit; cennectipnsmthe freturn axial @second Y.gear beinaseted herestrictionpf` the (magnetic, pull,

an axial magnetic ter-electrqmotiyeg-force the; @malsaine been @A131blues/trui? e Sad l" i ,-1231 appar Athe c om riallatalidirist steventposition, a shaft for'rotating v'said second gear, a source of current,and electro-magnetic means adapted when energized to move said secondgear axially into mesh with said rst gear and to rotate said shaft, thereturn axial movement of said' second gear being effected upon thestarting o'f the engine under its own power by the combined actions ofdecreased axial pull of said electro-magnetic means due to increasedcounter-electromotive force, the axial thrust of said helical gears andthe tension of said springs.

13. Starting mechanism for internal combustion engines, including, incombination, helical gears adapted to mesh with each other and transmitmotion from a starting motor to the engine, one of said gears beingmovable axially relative to the other into and out of engagementtherewith, and the inclination of the gear teeth being such that the endthrust thereon tends to hold the axially movable gear in engagement withthe other gear when it is rotated by the starting motor and will shiftit,.out of engagement therewith when it is rotated by the engine, andmeans for automatically and electrically shifting said axially movablegear into engagement with the other gear upon the energizing of themotor. 14. In an apparatus of the class described 1n gine, an electricmotor, a source of current, means for energizing said motor from saidsource of current, a gear operatively connected to said engine, a secondgear adapted with said first gear and normally disposedyset in an axialdirection from its meshing position, andmeans comprising alongitudinally movable shaft upon which said second gear is mounted,actuated by the motor in starting to move said second gear by saidlongitudinal movement in an axial direction into mesh -with said firstgear to effect driving connection between said motor and saidengine,said last mentioned means being adapted to automaticallydisengave the gears as the motor ceases to drive tlie engine, due to theincreased counter-electro motive'force of the motor when the starting ofthe engine has been effected.

*11oI combination, an internal combustion en- `With Sald rst gear andnormally disposed,`

Y 1 oset in an axialdirection from 4its meshing jf" '*position7 *and-Fmeans i `10mounted'ffor rotary/aand'longitudinal move- "mprisingl ashaft,

' two y subscribing Witnesses. "'`{ment/,"Y adapted toautomatically-move saidV i @second gear? larifaxial f' direction into'meslrl Y"fwith"Said.;fiit gar5'said' means being actuated by vthelnovementof thearmature of said motor due to its attraction by theeld 15magnet, and adapted to automatlcally dis- 1 engage the gearupon thedecrease 1n pull of said field magnets due 'to thev increasedcounter-electromotive `force ofthe motor 4 *When the startinglof theengine has been 29 eected.

` In `testimony whereof I have signed my name tothis specification inthe presence of K SAMUELNV. RUSHMORE. `VyVitness'es:

ZR. MILLWARD, ff

